It is well-known in the power distribution art that a panel board will occasionally be inadvertantly mis-wired whereby one energized line is connected to the neutral line connection while the neutral line is connected to one of the energized line connections. In such instance, the application of power will cause a voltage in excess of the normal line-to-neutral voltage to be applied to one load device, which will generally be damaged by the applied over-voltage. The other load, or loads, may become hazardous due to the phase reversal applied thereto. Normal over-current protection devices, such as fuses, circuit breakers and the like, will not protect each load device from these over-voltage effects as the current flowing therethrough will generally not be excessive until after the load device has been damaged.